Despite the warm and welcoming people, the local cuisine was questionable. In the case of the soup, I discovered what the ingredients in the bowl were after it had been eaten.

In the decades since, I hankered to return; but what of the children and their delicate digestive systems?

The dilemma is neatly resolved by Intrepid Travel's family tour with a guide to advise on  culinary and other  matters. Khoa meets our group of   six adults and seven children at a hotel among  the colonial piles and brutalist blocks that characterise Hanoi, in the north.

Like the architecture, we are  an eclectic mix: a single mother with her five and six-year-old boys; a couple with 13-year-old twin girls; and an older woman with her 12-year-old granddaughter – all from New Zealand.

We find common ground in our love of adventure travel; the girls decide everything is "faaaabulous"; and the boys take turns playing Minecraft.

Our first challenge is a game of inches, crossing the road where there  appear to be no rules: traffic lights and pedestrian crossings are simply suggestions.

Khoa is a lifesaver, literally, as he herds us across an intersection as scooter riders whiz by, chatting on mobile phones, with children on the back, and babies in front.

An image of a beaming Bill Clinton greets us at KOTO restaurant, where street kids are given food, clothing, and training, before working in five-star hotels, as part of a charity program.

In traditional style, rice paper rolls are delivered deconstructed, the stiff wrapping moistening upon contact with the stuffing.

The service is flawless – and there are Western options for fussy kids.

Interestingly, restaurants in Hanoi vary greatly in price, depending on whether the manager owns or rents the premises.

Avalon, overlooking the languid lake,  in the Old Quarter is especially good value for its traditional beef and chicken soups, pho bo and pho ga.

Here, we take a hair-raising cycle ride through its narrow streets, past women frying cha cha (fish), tubs of wriggling eels, and power lines like tangled kite strings.

On the sedate side of town, the Ho Chi Minh museum has Communist propaganda at its finest and where the revolutionary leader is so revered, queues to see his body in the mausoleum are kilometres long.

Vietnam had more than its share of invaders, mythologised in the creation of the thousands of plinths in Ha Long Bay, four hours' drive northeast of Hanoi.

In the legend of the dragon descending, each limestone structure rose up to stop water-borne raiders.

We board a junk for a tranquil trip across the mirrored waters, which are pocked with pollution.

Still, watching the sun set while sipping a gin and tonic on the deck? Priceless.

Dinner is a degustation, featuring fresh seafood, before we collapse in the comfortable  twin rooms below deck.

The  next day, we paddle kayaks into the grottos of Surprise Cave, bristling with monkeys.

Someone throws a small piece of cucumber, so the macaques scamper to the water's edge.

"They're so cute! Can I take one home?" six-year-old Jacob implores.

Back in Hanoi, we hop on a train to the royal city, Hue.

Hubby eyes the beds in our sleeper carriage with dismay: they're barely long enough for our nine-year-old son.

The food on board "will definitely make you sick" according to Khoa, so we prepare a picnic of fresh baguettes and tinned treats before playing cards until bedtime.

"It's like camping, but on a train!" our daughter Grace enthuses.

Despite the dramatic jerk every time we stop, the soporific rhythm lulls us into a deep sleep.

Hue is a small city of wide boulevards, imposing palaces, and golden temples.

Enjoying a cool breeze on top of a hill at Thien Mu Pagoda, we watch as one monk pats the children on the head for good luck, while another slumbers during a long chanting ceremony.

After a dragon boat ride along the Perfume River – so named because of the flowers that grew on the banks – we're invited into a family home for a 10-course dinner.

The 89-year-old matriarch breaks into a beaming smile of blackened teeth.

"In the old days, we used a chemical and jungle leaves to make our teeth black as a sign that we were married," she explains to Khoa. "That way, no one else would try to court us."

Her children and grandchildren prepare a delicious meal of fluffy spring rolls, caramel beef in a clay pot, tomatoes stuffed with pork mince, and jackfruit salad.

The kids scoff everything, while learning about how locals live.

A three-hour drive south from Hue to Hoi An passes soaring mountain ranges and sandy beaches.

Hoi An is a tailor's village, where you can get a suit made to measure for a-quarter of the price back home.

The service at Yaly Couture – which Khoa recommends – is extraordinary, including 3D imagery of your body shape.

The women and girls try on sample dresses, while the men and boys decamp to the bar next door.

After three fittings over two days, we end up with an evening gown, a man's suit, four corporate frocks, three girls' dresses, two shirts and two handmade pairs of shoes for under $800.

An antidote to the consumerism of Hoi An is a visit to a boarding house for orphaned and poor kids, run by the charity Children's Hope in Action.

"This centre gives them chance for further education,"  spokesperson Lai Le says. "We pay for books, uniforms, bicycles, medical bills, and there's a vegetable garden out the back so they learn how to feed themselves."

It's a valuable lesson for the kids, who come away with an understanding of the challenges faced by children in the developing world.

Another cultural lesson is learned at the Giota cooking school, in the garage of a family home. The compulsory Communist message blares from the radio at precisely 5pm. "Sorry, I can't turn it off!" our hilarious cook, Han, laughs. "The words aren't so bad, but the Party music is TERRIBLE."

Singing Happy at the top of our lungs, we make spring rolls in light latticed wrapping, a traditional pho bo, chicken and lemongrass stirfry, and green papaya salad.

This is a must-do, along with the mountain bike tour through rice paddies.

It's unnerving at first, weaving in and out of traffic with a child on the back, but soon we're careering through villages bathed in a golden sunset.

The ride is relaxed enough for grandmother Penny, who does the three hours with ease.

We meet a 90-year-old year old farmer, who teaches the kids how to water his meticulously maintained crops the old-fashioned way.

"How do they have so many plants?" Taj marvels. "I haven't seen a Bunnings anywhere!"

A fellow farmer offers us a ride on his buffalo: these beasts of burden haul the ploughs while trampling the crops to separate the rice. Despite the aggravated animal whipping me with his tail, the kids agree, "It's better than any ride at the show!"

Our bike ride ends with a boat trip, as Hoi An greets the dusk with twinkling lights and colourful lanterns.

In Ho Chi Minh City we stay at the Victory Hotel, a quality three-star, with comfortable king and single beds, bath and rain shower, double-glazing, free wi-fi, breakfast buffet, and pool on the roof.  The  hotel is walking distance to the War Remnants Museum, which houses the original of the photo – Kim Phuc running from a napalm attack – which precipitated an end to the Vietnam War.

Young children should avoid Level 1, as the images of Agent Orange victims are horrific.  We thought it  important for the kids to see them, but seven-year-old Grace had nightmares for weeks. Although peppered with propaganda, the museum provides an important perspective on the war, including the American and French land grab for tin and tungsten.

Two hours in our trusty mini-van takes us to the famed Cu Chi tunnels, where Viet Cong and villagers lived underground for up to a year at a time. It's quite claustrophobic in the tunnels, but there are regular exit points.  (Make sure you warn the kids: there are huge millipedes, realistic dummies of soldiers, and a shooting range next door.)

Our last night is straight from a James Bond film: a cruise on the NLTN canal, finishing with fireworks to celebrate Reunification Day.

Although initially sceptical, we'd highly recommend group family travel. Each night, the adults bond over $2 mojitos at one table, while the kids play at the next.

Khoa takes  us to restaurants that are  authentic but safe: no one is  sick. Once, he grabbed a mango smoothie as Gracie was about to take a sip: "No! That ice is from river water. I'll get you another one."

The "responsible travel" ethos means we only spend money in locally owned businesses, and it's cheap because everything is booked at wholesale rates.  As a family travel destination, Vietnam has come a long way from the days of goats' penis soup.

TRIP NOTES

MORE INFORMATION

intrepidtravel.com

GETTING THERE

Vietnam Airlines and Thai Airways fly from Australia to Vietnam see thaiairways.com, vietnamairlines.com.

WHILE YOU'RE THERE

The Intrepid 13-day Vietnam Family Holiday costs $1730 a person for accommodation, transport, 11 breakfasts, four lunches and one dinner. Airfares are extra. There's a 10 per cent discount for children under the age of 15. The minimum age is five. 

FIVE MORE THINGS TO DO WITH KIDS IN VIETNAM

- Watch the water puppet show in Hanoi.

- Visit Cua Dai Beach outside Hoi An.

- Marvel at the royal palaces in Hue.

- Take a day trip along the Mekong Delta.

- Play at the Dam Sen Water Park in Ho Chi Minh City.

 The writer was a guest of Intrepid Travel and Thai Airways.